Display type image sensor

ABSTRACT

A display type image sensor using thin-film photoelectric conversion elements that function as light emitting elements and light receiving elements so that the sensor can be used both as an active matrix display and as an image sensor, wherein pixels (PX) arranged in matrix each comprise: a first pixel portion (PXA) having a first conduction control circuit (SWA) supplied with a scan signal through a scan line (gate) and a first thin-film photoelectric conversion element ( 11 A) which can emit and receive light and connects to a first interconnect (D 21 ) and a second interconnect (D 22 ) through the first conduction control circuit (SWA); and a second pixel portion (PXB) having a second conduction control circuit (SWB) supplied with a scan signal through the same scan line (gate) and a second thin-film photoelectric conversion element ( 11 B) which can emit and receive light and connects to the first interconnect (D 21 ) and a third interconnect (D 23 ) through the second conduction control circuit (SWB).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a new apparatus (image sensor apparatushaving an additional display device function) that can be used both asan active-matrix-type display device and as an image sensor.

2. Description of the Related Art

An active-matrix-type display device in which current-control-typelight-emitting elements, such as EL (electroluminescence) elements orLEDs (light-emitting diodes), are used is disclosed in, for example,Japanese Unexamined Patent Publication Nos. 8-54836 and 8-129358. Sinceany of the light-emitting elements used for this type of display deviceemits light by itself, there are advantages that, unlike liquid-crystaldisplay devices, it does not require a backlight, and dependence uponviewing angle is small. Meanwhile, as facsimile machines are in themidst of becoming more widespread in ordinary households, there has beena demand for more inexpensive ones as household electrical appliances.

However, since image sensors used in conventional facsimile machinesrequire an optical system, a mechanical system, sensors, an illuminationsystem, and the like, which are expensive, it is difficult to achievelowering of the price of a facsimile machine.

SUMMARY OF THE INVENTION

Here, the inventors of the present invention have taken note of the factthat the current-control-type light-emitting element functions also as aPD (photodiode) element depending on the driving conditions and haveproposed a new apparatus which can be used both as an active-matrix-typedisplay device and as an image sensor.

In other words, an object of the present invention is to provide animage sensor apparatus having an additional display device functionwhich can be used both as an active-matrix-type display device and as animage sensor by using thin-film optoelectronic transducers whichfunction as light-emitting elements and light-receiving elements.

In order to solve the above-described problems, an image sensorapparatus having an additional display device function of the presentinvention includes: a plurality of pixels arranged in matrix, scanninglines to which a scanning signal for selecting the pixels in sequence issupplied, and first to third wirings used as signal lines when lightemission or light reception is performed by the pixels selected by thescanning line, wherein the pixels includes first pixel section having afirst conduction control circuit to which the scanning signal issupplied through the scanning line, and a first thin-film optoelectronictransducer capable of performing light emission and light reception,connected to the first wiring and the second wiring via the firstconduction control circuit; and a second pixel section having a secondconduction control circuit to which the scanning signal is suppliedthrough the scanning line, and a second thin-film optoelectronictransducer capable of performing light emission and light reception,connected to the first wiring and the third wiring via the secondconduction control circuit.

In the image sensor apparatus having an additional display devicefunction of the present invention, since each pixel is formed with firstand second thin-film optoelectronic transducers which function as alight-emitting element and a light-receiving element, by only changingthe method of driving these thin-film optoelectronic transducers, it ispossible to use the image sensor apparatus having an additional displaydevice function as an image sensor apparatus and as a display device.Also, in the image sensor apparatus having an additional display devicefunction of the present invention, since each optoelectronic transduceris formed of a thin-film optoelectronic transducer, it can bemanufactured by a semiconductor process in a manner similar to that foran active-matrix substrate of a liquid-crystal display device.Furthermore, since an optical system, a mechanical system, sensors,illumination, and the like, which are expensive, are not required, thereadout section and the like of a facsimile machine can be lowered inprice.

In the present invention, there is a case in which the conductioncontrol circuit is composed of one thin-film transistor (hereinafterreferred to as a TFT) and there is a case in which the conductioncontrol circuit is composed of thin-film transistors of two stages, ineach of the first and second pixel sections.

In the case where the conduction control circuit is composed of one TFT,first, the first conduction control circuit and the second conductioncontrol circuit are each formed with one TFT in which the scanningsignal is supplied to the gate electrode. Of these TFTs, the TFT of thefirst conduction control circuit is connected at one of its source anddrain regions to the second wiring and connected at the other to thepixel electrode of the first thin-film optoelectronic transducer. Also,the TFT of the second conduction control circuit is connected at one ofits source and drain regions to the third wiring and connected at theother to the pixel electrode of the second thin-film optoelectronictransducer.

With such a construction as described above, preferably, a switchingcircuit is provided such that, when the thin-film optoelectronictransducer is used as a light-emitting element, the wiring of the secondand third wirings to which the thin-film optoelectronic transducer isconnected is connected to an output circuit for a switch on/off controlsignal, and when the thin-film optoelectronic transducer is used as alight-receiving element, the wiring of the second and third wirings towhich the thin-film optoelectronic transducer is connected is connectedto a photocurrent detection circuit, and the first wiring is connectedto a constant-voltage power source. With this construction, by onlyswitching the connected state of the second and third wirings by theswitching circuit, it is possible to cause both the first and secondpixel sections to function as a light-emitting section or alight-receiving section and also possible to cause one of them tofunction as a light-emitting section and the other to function as alight-receiving section.

In the present invention, when the conduction control circuit is formedof TFTs of two stages, first, the first conduction control circuit andthe second conduction control circuit are each formed with a first TFTin which the scanning signal is supplied to the gate electrode and asecond TFT in which the gate electrode is connected to the first wiringthrough the first TFT. Of these TFTs, the second TFT of the firstconduction control circuit is connected at one of its source and drainregions to the second wiring and connected at the other to the pixelelectrode of the first thin-film optoelectronic transducer. Also, thesecond TFT of the second conduction control circuit is connected at oneof its source and drain regions to the third wiring and connected at theother to the pixel electrode of the second thin-film optoelectronictransducer.

With such a construction as described above, a switching circuit isprovided such that, when the thin-film optoelectronic transducer is usedas a light-emitting element, the wiring of the second and third wiringsto which the thin-film optoelectronic transducer is connected isconnected to a constant-voltage power source, and when the thin-filmoptoelectronic transducer is used as a light-receiving element, thewiring of the second and third wirings to which the thin-filmoptoelectronic transducer is connected is connected to a photocurrentdetection circuit, and the first wiring is connected to an outputcircuit for receiving a signal for controlling the conduction state ofthe second TFT. With such a construction, by only switching theconnected state of the second and third wirings by the switchingcircuit, it is possible to cause both the first and second pixelsections to function as a light-emitting section or a light-receivingsection, and also possible to cause one of them to function as alight-emitting section and the other to function as a light-receivingsection.

In the present invention, the formation area of the pixel electrode ofthe first thin-film optoelectronic transducer and the formation area ofthe pixel electrode of the second thin-film optoelectronic transducerare preferably intermingled with each other. With such a construction,when the image sensor apparatus having an additional display devicefunction is used as an image sensor apparatus, the light which is outputfrom the side of the pixel section that functions as a light-emittingsection is reflected by a readout object, such as a document, a drawing,or a photograph, and efficiently reaches the side of the pixel sectionthat functions as a light-receiving section.

In the present invention, the formation area of the pixel electrode ofthe first thin-film optoelectronic transducer and the formation area ofthe pixel electrode of the second thin-film optoelectronic transducerare preferably such that the center-of-gravity positions of both areclose to each other in comparison with a construction in which the outerframe of the pixel electrode is partitioned by a straight line. Forexample, the formation area of the pixel electrode of the firstthin-film optoelectronic transducer is preferably surrounded by theformation area of the pixel electrode of the second thin-filmoptoelectronic transducer. In this case, the formation area of the pixelelectrode of the first thin-film optoelectronic transducer is preferablyin the central portion of the formation area of the pixel electrode ofthe second thin-film optoelectronic transducer. With such a constructionas described above, when the image sensor apparatus having an additionaldisplay device function is used as an image sensor apparatus, the lightwhich is output from the side of the pixel section that functions as alight-emitting section is reflected by a readout object, such as adocument, a drawing, or a photograph, and efficiently reaches the sideof the pixel section that functions as a light-receiving section.

In the present invention, a light-shielding layer is preferably formedbetween the pixel electrode of the first thin-film optoelectronictransducer and the pixel electrode of the second thin-filmoptoelectronic transducer. With such a construction, even if light isemitted in all directions from the side of the pixel section whichfunctions as a light-emitting section, it is possible for thelight-shielding layer to prevent the light from leaking to the portionof the pixel section which functions as a light-receiving section.Therefore, it is possible to read an image from a readout object at ahigh S/N ratio.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an equivalent circuit diagram of an active matrix used for animage sensor apparatus having an additional display device functionaccording to a first embodiment of the present invention.

FIG. 2 is an enlarged plan view showing one of a plurality of pixelsformed in an active matrix of the image sensor apparatus having anadditional display device function shown in FIG. 1.

FIGS. 3(A) and 3(B) are each a sectional view showing the constructionof each element formed in the pixel shown in FIG. 2.

FIGS. 4(A) and 4(B) are each a waveform chart of a scanning signal andthe like supplied to two adjacent pixels in the active matrix of theimage sensor apparatus having an additional display device functionshown in FIG. 1.

FIG. 5 is an equivalent circuit diagram of an active matrix used for animage sensor apparatus having an additional display device functionaccording to a second embodiment of the present invention.

FIG. 6 is an enlarged plan view showing one of a plurality of pixelsformed in an active matrix of the image sensor apparatus having anadditional display device function shown in FIG. 5.

FIGS. 7(A) and 7(B) are each a sectional view showing the constructionof each element formed in the pixel shown in FIG. 6.

FIGS. 8(A) and 8(B) are each a waveform chart of a scanning signal andthe like supplied to two adjacent pixels in an active matrix of theimage sensor apparatus having an additional display device functionshown in FIG. 5.

FIGS. 9(A) and 9(B) are each an illustration showing the formation areaof two pixel electrodes formed in each pixel of an active matrix in animage sensor apparatus having an additional display device functionaccording to a third embodiment of the present invention.

FIG. 10 is an illustration showing the formation area of two pixelelectrodes formed in each pixel of an active matrix in an image sensorapparatus having an additional display device function according to afourth embodiment of the present invention.

FIG. 11(A) is an illustration showing the formation area of two pixelelectrodes formed in each pixel of an active matrix in an image sensorapparatus having an additional display device function according to afifth embodiment of the present invention; and FIG. 11(B) is anillustration showing the operation and the effect when the constructionis formed as described above.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The embodiments of the present invention will be described withreference to the drawings.

First Embodiment

(Overall Construction of Active-matrix Substrate)

FIGS. 1 to 4(B) are respectively an equivalent circuit diagram of anactive matrix used for an image sensor apparatus having an additionaldisplay device function, an enlarged plan view showing one of aplurality of pixels formed in this active matrix, sectional viewsshowing the construction of each element formed in this pixel, andwaveform charts showing potential fluctuation in two pixels.

An active-matrix substrate used in the image sensor apparatus having anadditional display device function of this embodiment is manufactured bya semiconductor process in a manner similar to that for an active-matrixsubstrate of a liquid-crystal display device. As shown in FIGS. 1 and 2,in an image sensor apparatus 1 having an additional display devicefunction of this embodiment, a plurality of scanning lines “gate” areformed on a transparent substrate 2. In the direction intersecting thedirection in which these scanning lines “gate” are extended, a firstwiring D11 that functions as a common wiring for supplying voltage, andsecond and third wirings D12 and D13 that function as a signal line areformed, with each pixel PX (pixels PX11, PX12, PX21, PX22) being formedin matrix in such a manner as to correspond to the intersection portionof the second wiring D12 (or the third wiring D13) and the scanninglines “gate”. In the end portion of the scanning line “gate”, ascanning-side driving circuit 20 for outputting a pulse for selecting apixel as a scanning signal to this scanning line “gate” is formed.

(Construction of the Pixel)

As shown in FIGS. 1 to 3(B), in this embodiment, each pixel PX is formedwith a first pixel section PXA comprising a first conduction controlcircuit SWA to which a scanning signal for selecting a pixel is suppliedthrough the scanning line “gate” and a first thin-film optoelectronictransducer 11A which is connected to the first wiring D11 and the secondwiring D12 in a circuit manner through the first conduction controlcircuit SWA; and a second pixel section PXB comprising a secondconduction control circuit SWB to which the scanning signal is suppliedthrough the scanning line “gate” for common use with this first pixelsection PXA and a second thin-film optoelectronic transducer 11B whichis connected to the first wiring D11 and the third wiring D13 in acircuit manner through the second conduction control circuit SWB.Although not shown in FIGS. 2 and 3, in each of the first and secondpixel sections PXA and PXB, holding capacitors 13A and 13B are formed insuch a manner as to be connected in parallel to the first and secondthin-film optoelectronic transducers 11A and 11B.

The first and second conduction control circuits SWA and SWB are formedof p-channel-type TFTs 10A and 10B including a gate electrode to which ascanning signal is supplied from the scanning line “gate”, respectively.The TFT 10A on the side of the first conduction control circuit SWA isconnected at one of its source and drain regions S/D to the secondwiring D12 and connected at the other to a pixel electrode PEA of thefirst thin-film optoelectronic transducer 11A. The TFT 10B on the sideof the second conduction control circuit SWB is connected at one of itssource/drain regions S/D to the third wiring D13 and connected at theother to a pixel electrode PEB of the second thin-film optoelectronictransducer 11B.

FIGS. 3(A) and 3(B) show a section along the line A-A′ of FIG. 2 and asection along the line B-B′ of FIG. 2, respectively. As shown in FIGS.3(A) and 3(B), the basic constructions of the first and second pixelsections PXA and PXB are the same, and the TFTs 10A and 10B whichconstitute the first and second conduction control circuits SWA and SWBare each formed with a channel region 61, source/drain regions S/Dformed on both sides of the channel region 61, a gate insulation film 62formed at least on the surface of the channel region 61, and a gateelectrode 63 formed on the surface of this gate insulation film 62, withan interlayer insulation film 64 being formed on the surface of the gateelectrode 63. The second and third wirings D12 and D13 are connectedelectrically to one of the source/drain regions S/D, respectively,through the contact hole of this interlayer insulation film 64. Thepixel electrodes PEA and PEB of the first and second thin-filmoptoelectronic transducers 11A and 11B are connected electrically to theother of the source/drain regions S/D, respectively. Although not shownin FIG. 3(B), in each of the first and second pixel sections PXA andPXB, holding capacitors 13A and 13B which are connected in parallel tothe first and second thin-film optoelectronic transducers 11A and 11Bare formed, as described with reference to FIG. 1. These holdingcapacitors 13A and 13B can be formed by extending, for example, thepixel electrodes PEA and PEB or that part of the source/drain regionsS/D, which is connected electrically to the pixel electrodes PEA andPEB, and by causing them to oppose a counter electrode OP through theinsulation film. It is also possible to form the holding capacitors 13Aand 13B by forming a capacitance line in such a manner so as to passthrough the first and second pixel sections PXA and PXB and by causingthis capacitance line to oppose the extended portion of the source/drainregions S/D or the pixel electrodes PEA and PEB through the insulationfilm. In this case, the capacitance line is set at a fixed potential.

(Thin-film Optoelectronic Transducer)

The first and second thin-film optoelectronic transducers 11A and 11Bhave the same construction and function as either a light-emittingelement or a light-receiving element. That is, in the first thin-filmoptoelectronic transducer 11A, a transparent pixel electrode PEA formedof an ITO film, a positive-hole injection layer VA, an organicsemiconductor film SA, and a counter electrode OP formed of alithium-containing metal film such as aluminum or calcium aremultilayered in this sequence. Also in the second thin-filmoptoelectronic transducer 11B, similarly, a transparent pixel electrodePEB formed of an ITO film, a positive-hole injection layer VB, anorganic semiconductor film SB, and a counter electrode OP formed of alithium-containing metal film such as aluminum or calcium aremultilayered in this sequence, each of these layers being a layer formedat the same time as the pixel electrode PEA, the positive-hole injectionlayer VA, the organic semiconductor film SA, and the counter electrodeOP of the first thin-film optoelectronic transducer 11A.

A case in which the thin-film optoelectronic transducer functions as alight-emitting element will be described first. In the first and secondthin-film optoelectronic transducers 11A and 11B, since these are usedas light-emitting elements (current-control-type light-emittingelements), when a voltage is applied by assigning the counter electrodeOP and the pixel electrodes PEA and PEB as a negative pole and apositive pole, respectively, current (driving current) which flowsthrough the organic semiconductor films SA and SB increases sharply in astate in which the applied voltage exceeds a threshold voltage of thethin-film optoelectronic transducer, causing the first and secondthin-film optoelectronic transducers 11A and 11B to emit light as an ELelement or an LED element. This light is reflected by the counterelectrode OP, passes through the transparent pixel electrodes PEA andPEB, and is output.

Next, a case in which the thin-film optoelectronic transducer functionsas a light-receiving element will be described. When light reaches thefirst and second thin-film optoelectronic transducers 11A and 11Bthrough the transparent substrate 2 and the transparent pixel electrodesPEA and PEB, photocurrent is generated in the organic semiconductorfilms SA and SB. In this case, the thin-film optoelectronic transducerfunctions as a light-receiving element that generates a potentialdifference between the counter electrode OP and the pixel electrodes PEAand PEB.

When manufacturing the first and second thin-film optoelectronictransducers 11A and 11B of such a construction, in this embodiment,after a black resist layer is formed on the surface of the interlayerinsulation film 64, the positive-hole injection layers VA and VB and theorganic semiconductor films SA and SB are formed, the resist is left insuch a manner as to surround the area which is to be the light-emittingarea or the light-receiving area, and a bank layer “bank” is formed.After the bank layer “bank” is formed, a liquid material (precursor) forforming the positive-hole injection layers VA and VB is discharged froman ink jet head with respect to the inner area of the bank layer “bank”,and the positive-hole injection layers VA and VB are formed in the innerarea of the bank layer “bank”. Similarly, a liquid material (precursor)for forming the organic semiconductor films SA and SB is discharged fromthe ink jet head with respect to the inner area of the bank layer“bank”, and the organic semiconductor films SA and SB are formed in theinner area of the bank layer “bank”. Here, since the bank layer “bank”is formed of a resist, it is water-repellent. In contrast, since theprecursors of the positive-hole injection layers VA and VB and theorganic semiconductor films SA and SB use a hydrophilic solvent as amain solvent, the coating areas of the positive-hole injection layers VAand VB and the organic semiconductor films SA and SB are surely definedby the bank layer “bank”, and do not extend out to the adjacent pixelsection. Therefore, it is possible to form the positive-hole injectionlayers VA and VB and the organic semiconductor films SA and SB onlywithin the predetermined area. Further, a bank layer “bank” having alight-shielding property (light-shielding layer) is formed between thepixel electrode PEA of the first pixel section PXA and the pixelelectrode PEB of the second pixel section PXB. However, if the barrierplate formed of the bank layer “bank” has a height of about 1 μm inadvance, the bank layer “bank” functions sufficiently as a barrier plateeven if the bank layer “bank” is not water-repellent. If the bank layer“bank” is formed in advance, even when the positive-hole injectionlayers VA and VB and the organic semiconductor films SA and SB areformed by a coating method instead of an ink jet method, the formationarea thereof can be defined.

In the thin-film optoelectronic transducers 11A and 11B, although lightemission efficiency is slightly decreased, there is a case in which thepositive-hole injection layers VA and VB are omitted. Further, when anelectron injection layer is formed on the opposite side of the organicsemiconductor films SA and SB in place of the positive-hole injectionlayers VA and VB, there is a case in which both the electron injectionlayer and the positive-hole injection layers VA and VB are formed.

(Driving Circuit)

As can be seen from FIG. 2, the counter electrode OP is formed at leaston the pixel area, and in this embodiment, is formed in strip in such amanner as to extend across a plurality of pixels PX as a commonelectrode among the pixels PX. As shown in FIG. 1, this counterelectrode OP itself is used as the first wiring D11, and it is connectedto a constant-voltage power source cc.

In this embodiment, the construction is formed as described below suchthat in all the pixels PX, the first thin-film optoelectronic transducer11A and the second thin-film optoelectronic transducer 11B can be usedas a light-emitting element or a light-receiving element, and one of theoptoelectronic transducer 11A and the second thin-film optoelectronictransducer 11B can be used as a light-emitting element and the other asa light-receiving element.

Referring again to FIG. 1, a first data-side driving circuit 301 foroutputting a signal for controlling the switched on/off state to thesecond wiring D12, and a second data-side driving circuit 302 foroutputting a signal for controlling the switched on/off state to thethird wiring D13 are formed on the transparent substrate 2. Also formedon the transparent substrate 2 are a first photocurrent detectioncircuit 501 for detecting photocurrent from the second wiring D12 whichflows when the first thin-film optoelectronic transducer 11A receiveslight, and a second photocurrent detection circuit 502 for detectingphotocurrent from the third wiring D13 which flows when the secondthin-film optoelectronic transducer 11B receives light. Here, the firstphotocurrent detection circuit 501 and the second photocurrent detectioncircuit 502 contain therein a very-small-current amplification circuit,a voltage amplification circuit, and the like, so that a very smallvariation of each wiring is monitored.

(Switching Circuit)

Also, as shown in FIG. 1, formed on the transparent substrate 2 are afirst switching circuit 401 that connects the second wiring D12 to thefirst data-side driving circuit 301 when the first thin-filmoptoelectronic transducer 11A is used as a light-emitting element andthat connects the second wiring D12 to the first photocurrent detectioncircuit 501 when the first thin-film optoelectronic transducer 11A isused as a light-receiving element, and a second switching circuit 402that connects the third wiring D13 to the second data-side drivingcircuit 302 when the second thin-film optoelectronic transducer 11B isused as a light-emitting element and that connects the third wiring D13to the second photocurrent detection circuit 502 when the secondthin-film optoelectronic transducer 11B is used as a light-receivingelement.

In this example, the first switching circuit 401 is formed with signallines cg1 and sg1 to which the signals whose polarity is inverted withrespect to the other are respectively supplied, and the second switchingcircuit 402 is formed with signal lines cg2 and sg2 to which the signalswhose polarity is inverted with respect to the other are respectivelysupplied. These signal lines cg1, sg1, cg2, and sg2 are connected to thegate electrodes of n-channel-type TFTs 41, 42, 43, and 44, respectively.The TFT 41 is constructed so as to control the connected state of thefirst photocurrent detection circuit 501 and the second wiring D12, andthe TFT 42 is constructed so as to control the connected state of thefirst data-side driving circuit 301 and the second wiring D12.Similarly, the TFT 43 is constructed so as to control the connectedstate of the second photocurrent detection circuit 502 and the thirdwiring D13, and the TFT 44 is constructed so as to control the connectedstate of the second data-side driving circuit 302 and the third wiringD13.

(Method of Use)

When the image sensor apparatus 1 having an additional display devicefunction constructed as described above is used as a contact-type imagesensor apparatus, a readout object, such as a photograph, from which animage is to be read, is brought into close contact with the rear surfaceof the transparent substrate 2. Here, in each pixel PX, when the firstthin-film optoelectronic transducer 11A is used as a light-emittingelement and the second thin-film optoelectronic transducer 11B as alight-receiving element, the first switching circuit 401 causes the TFT41 to be turned off and the TFT 42 to be turned on. In contrast, thesecond switching circuit 402 causes the TFT 43 to be turned on and theTFT 44 to be turned off.

In this state, the signals of waveforms shown in FIGS. 4(A) and 4(B) areoutput to the scanning line “gate” and the second wiring D12.

FIGS. 4(A) and 4(B) show a scanning signal Vgate supplied to eachscanning line “gate” in two adjacent pixels PX (the pixel PX11 on thepre-stage side, and the pixel PX21 on the post-stage side) in thedirections in which the first to third wirings D11, D12, and D13 areextended (the direction intersecting the scanning line “gate”), thepotential level of the first wiring D11, a signal VD12 for controllingthe switch on/off, which is supplied to the second wiring D12, thepotential fluctuation of the third wiring D13, and the potentialfluctuation of the pixel electrode PEA of the first thin-filmoptoelectronic transducer 11A used as a light-emitting element.

As can be seen from FIGS. 4(A)-(B), a scanning signal Vgate for causingthe TFTs 10A and 10B to be turned on/off in each, pixel and selectingeach pixel in sequence is supplied to the scanning line “gate”, whereasa switch on/off control signal VD12 for switching the first thin-filmoptoelectronic transducer 11A between switched on and off states in thefirst pixel section PXA is supplied to the second wiring D12. Therefore,in the pixel PX selected by the scanning line “gate”, the firstthin-film optoelectronic transducer 11A is switched from theswitched-off state to the switched-on state for a predetermined periodin accordance with the switch on/off control signal VD12 in the firstpixel section PXA and returns to a switched-off state again. In thisperiod, in the second pixel section PXB, the second thin-filmoptoelectronic transducer 11B receives the light which is reflected by areadout object, such as a photograph, from the first pixel section PXA.As a result, photocurrent flows in the second thin-film optoelectronictransducer 11B, and in accordance with this, a predetermined potentialdifference is generated between the pixel electrode PEB of the secondthin-film optoelectronic transducer 11B and the counter electrode OP.Since this potential difference appears in the third wiring D13, thiscan be detected in sequence by the second photocurrent detection circuit502. Such an operation is performed by each pixel selected in sequencein accordance with a scanning signal output to the scanning line “gate”from the scanning-side driving circuit 20. Therefore, it is possible forthe image sensor apparatus 1 having an additional display devicefunction as a contact-type image sensor apparatus to read imageinformation from a readout object, such as a photograph.

The image information read in this way and the like can be displayed bythe image sensor apparatus 1 having an additional display devicefunction. That is, the image information read herein from a readoutobject, such as a photograph, is recorded in an information recordingdevice, such as a RAM, and when it is displayed, a modulation imagesignal in accordance with the image information is sent to the secondwiring D12 from the first data-side driving circuit 301. As a result, inthe pixel PX selected in sequence by a scanning signal supplied from thescanning line “gate”, the switched on/off state of the first thin-filmoptoelectronic transducer 11A of the first pixel section PXA iscontrolled in accordance with the modulation image signal, and a desiredimage is displayed.

When such a display operation is performed, if the second switchingcircuit 402 causes the TFT 43 to be turned off and the TFT 44 to beturned on and the modulation image signal is sent from the seconddata-side driving circuit 302 to the third wiring D13, it is alsopossible for the second thin-film optoelectronic transducer 11B of thesecond pixel section PXB to control the switched on/off state inaccordance with the modulation image signal. When the display operationis performed by both the first and second pixel sections PXA and PXB asdescribed above, it is possible to produce a display having higherluminance.

In contrast to the above example, if the first and second switchingcircuits 401 and 402 cause the TFTs 41 and 43 to be turned on and theTFTs 42 and 44 to be turned off, it is possible to use the respectivefirst and second thin-film optoelectronic transducers 11A and 11B as alight-receiving element in both the first and second pixel sections PXAand PXB. As a result of the above, a reading operation with highersensitivity is possible.

(Advantages of this Embodiment)

As has been described above, in the image sensor apparatus 1 having anadditional display device function of this embodiment, since each pixelPX is formed with the first and second thin-film optoelectronictransducers 11A and 11B that function as a light-emitting element and alight-receiving element, by only changing the method of driving thesethin-film optoelectronic transducers, it is possible to use the imagesensor apparatus 1 having an additional display device function as animage sensor apparatus and a display device. Further, in the imagesensor apparatus 1 having an additional display device function of thisembodiment, each element can be manufactured by a semiconductor processand since an optical system, a mechanical system, sensors, illumination,and the like, which are expensive, are not required, the readout sectionand the like of a facsimile machine can be lowered in price.

Furthermore, by only switching the connected state of the second andthird wirings D12 and D13 by the switching circuits 401 and 402, it ispossible to cause both the first and second pixel sections PXA and PXBto function as a light-emitting section or a light-receiving section,and it is also possible to cause one of them to function as alight-emitting section and the other to function as a light-receivingsection.

Since a light-shielding bank layer “bank” is formed between the pixelelectrode PEA of the first pixel section PXA and the pixel electrode PEBof the second pixel section PXB, even if light is emitted in alldirections from the side of the first pixel section PXA which functionsas a light-emitting section, it is possible for the bank layer “bank” toprevent the light from leaking to the second pixel section PXB whichfunctions as a light-receiving section. Therefore, it is possible toread an image from a readout object at a high S/N ratio.

Second Embodiment

(Overall Construction of Active-matrix Substrate)

FIGS. 5 to 8(B) are respectively an equivalent circuit diagram of anactive matrix used for an image sensor apparatus having an additionaldisplay device function, an enlarged plan view showing one of aplurality of pixels formed in this active matrix, sectional viewsshowing the construction of each element formed in this pixel, andwaveform charts showing potential fluctuation in two pixels. In thefollowing description, components having functions common to those ofthe first embodiment are given the same reference numerals, andaccordingly, a detailed description thereof has been omitted.

An active-matrix substrate is also manufactured by a semiconductorprocess in a manner similar to that for an active-matrix substrate of aliquid-crystal display device used for an image sensor apparatus havingan additional display device function of this embodiment. As shown inFIGS. 5 and 6, also in the image sensor apparatus 1 having an additionaldisplay device function of this embodiment, on a transparent substrate2, a first wiring D21, a second wiring D22, and a third wiring D23 areformed in the direction intersecting the direction in which the scanninglines “gate” extend, with each pixel PX (pixels PX11, PX12, PX21, PX22)being formed in matrix as a result of the intersection of the first tothird wirings D21, D22, and D23 and the scanning lines “gate”. Further,a counter electrode OP is formed at least on the pixel region, and alsoin this embodiment, is formed in strip in such a manner as to extendacross a plurality of pixels PX as a common electrode among the pixelsPX.

(Construction of the Pixel)

As shown in FIGS. 5 to 8(B), each of the pixels PX is formed with firstand second pixel sections PXA and PXB. The first pixel section PXA isformed with a first conduction control circuit SWA to which a scanningsignal for selecting pixels is supplied through the scanning line “gate”and a first thin-film optoelectronic transducer 11A in which one of theelectrodes (pixel electrode PEA) is connected through this firstconduction control circuit SWA in a circuit manner to both the firstwiring D21 and the second wiring D22. Also, the second pixel section PXBis formed with a second conduction control circuit SWB to which thescanning signal is supplied through the scanning line “gate” for commonuse with the first pixel section PXA which, together this pixel section,constitutes one pixel PX, and a second thin-film optoelectronictransducer 11B in which one of the electrodes (pixel electrode PEB) isconnected through this second conduction control circuit SWB in acircuit manner to both the first wiring D21 and the third wiring D23.Here, in the first and second thin-film optoelectronic transducers 11Aand 11B, the other electrode is formed as a counter electrode OP forcommon use.

The first and second conduction control circuits SWA and SWB includeTFTs 10C and 10E in which a scanning signal is supplied to the gateelectrode, and second TFTs 10D and 10F in which the gate electrode isconnected to the first wiring D21 through these first TFTs 10C and 10E,respectively. In this example, the TFTs 10C and 10E are of an n-channeltype, and the TFTs 10D and 10F are of a p-channel type. The second TFT10D of the first conduction control circuit SWA is connected at one ofits source and drain regions S/D to the second wiring D22 and connectedat the other to the pixel electrode PEA of the first thin-filmoptoelectronic transducer 11A. The TFT 10F of the second conductioncontrol circuit SWB is connected at one of its source and drain regionsS/D to the third wiring D23 and connected at the other to the pixelelectrode PEB of the second thin-film optoelectronic transducer 11B.Although not shown in FIGS. 6, 7(A) and 7(B), in each of the first andsecond pixel sections PXA and PXB, one of the electrodes of the holdingcapacitors 13A and 13B is connected to the gate electrodes of the secondTFTs 10D and 10F so as to perform the function of holding the electricalpotential applied to the gate electrode.

As the sections along the line C-C′ and along the line D-D′ of FIG. 6and the sections along the line E-E′ and along the line F-F′ of FIG. 6are shown in FIGS. 7(A) and 7(B), respectively, the basic constructionsof the first and second pixel sections PXA and PXB are the same. Thefirst TFTs 10C and 10E and the second TFTs 10D and 10F which constitutethe first and second conduction control circuits SWA and SWB are eachformed with a channel region 61, source/drain regions S/D formed on bothsides of this channel region 61, a gate insulation film 62 formed atleast on the surface of the channel region 61, a gate electrode 63formed on the surface of this gate insulation film 62, and a firstinterlayer insulation film 64 formed on the surface of this gateelectrode 63.

In the first TFTs 10C and 10E which are constituents of the first andsecond conduction control circuits SWA and SWB, the first wiring D21 iselectrically connected to one of the source/drain regions S/D throughthe contact hole of the interlayer insulation film 64. A potentialholding electrode 65 is electrically connected to the other of thesource/drain regions S/D of the TFTs 10C and 10E through the contacthole of the interlayer insulation film 64, and this potential holdingelectrode 65 is electrically connected to the extended portion 630 ofthe gate electrode 63 of the second TFTs 10D and 10F.

A second interlayer insulation film 66 is formed on the surfaces of thepotential holding electrode 65 and the first wiring D21.

In the second TFT 10D which is a constituent of the first conductioncontrol circuit SWA, the second wiring D22 is electrically connected toone of the source/drain regions S/D through the contact hole of theinterlayer insulation film 64. In the second TFT 10F which is aconstituent of the second conduction control circuit SWB, the thirdwiring D23 is electrically connected to one of the source/drain regionsS/D through the contact hole of the interlayer insulation film 64. Arelay electrode 67 is electrically connected to the other of thesource/drain regions S/D of the second TFTs 10D and 10F through thecontact hole of the interlayer insulation film 64, and the pixelelectrodes PEA and PEB are electrically connected to this relayelectrode 67 through the contact hole of the interlayer insulation film66.

Although not shown in FIGS. 7(A)-(B), as described with reference toFIGS. 4(a)-(B), in each of the first and second pixel sections PXA andPXB, one of the electrodes of the holding capacitors 13A and 13B isconnected to the gate electrode 63 of the first TFTs 10C and 10E. Forexample, the gate electrodes 63 of the second TFTs 10D and 10F extend tobelow the second wiring D22 or the third wiring D23 and are made tooppose each other via the interlayer insulation film 64. These holdingcapacitors 13A and 13B may be formed in such a way that, for example, acapacitance line is formed in such a manner as to pass the first andsecond pixel sections PXA and PXB and this capacitance line is made tooppose the potential holding electrode 65 through the interlayerinsulation film 64. In this case, the capacitance line is held at afixed potential.

(Thin-film Optoelectronic Transducer)

The first and second thin-film optoelectronic transducers 11A and 11Bhave the same construction, as described in the first embodiment, andmay function as either a light-emitting element or a light-receivingelement. That is, in the first and second thin-film optoelectronictransducers 11A and 11B, transparent pixel electrodes PEA and PEB formedof an ITO film, positive-hole injection layers VA and VB, organicsemiconductor films SA and SB, and a counter electrode OP formed of alithium-containing metal film such as aluminum or calcium aremultilayered in this sequence, each of these layers being a layer formedat the same time as on the side of the first thin-film optoelectronictransducer 11A and the side of the second thin-film optoelectronictransducer 11B.

A case in which the thin-film optoelectronic transducer functions as alight-emitting element will be described first. In the first and secondthin-film optoelectronic transducers 11A and 11B, since these are usedas light-emitting elements, when a voltage is applied by assigning thecounter electrode OP and the pixel electrodes PEA and PEB as a negativepole and a positive pole, respectively, current (driving current) whichflows through the organic semiconductor films SA and SB increasessharply in a state in which the applied voltage exceeds a thresholdvoltage of the thin-film optoelectronic transducer, causing the firstand second thin-film optoelectronic transducers 11A and 11B to emitlight as an EL element or an LED element. This light is reflected by thecounter electrode OP, and is output through the transparent pixelelectrodes PEA and PEB and the transparent substrate 2.

A case in which the thin-film optoelectronic transducer functions as alight-receiving element will be described. When light reaches the firstand second thin-film optoelectronic transducers 11A and 11B through thetransparent substrate 2 and the transparent pixel electrodes PEA andPEB, photocurrent is generated in the organic semiconductor films SA andSB. In this case, the thin-film optoelectronic transducer functions as alight-receiving element which generates a potential difference betweenthe counter electrode OP and the pixel electrodes PEA and PEB.

When manufacturing the first and second thin-film optoelectronictransducers 11A and 11B of such a construction, similarly to the firstembodiment, after a black resist layer is formed on the surface of theinterlayer insulation film 66, positive-hole injection layers VA and VBand organic semiconductor films SA and SB are formed, the resist is leftin such a manner as to surround the area which is to be thelight-emitting area or the light-receiving area, and a bank layer “bank”is formed. After the bank layer “bank” is formed, a liquid material(precursor) for forming the positive-hole injection layers VA and VB isdischarged from an ink jet head with respect to the inner area of thebank layer “bank”, and the positive-hole injection layers VA and VB areformed in the inner area of the bank layer “bank”. Similarly, a liquidmaterial (precursor) for forming the organic semiconductor films SA andSB is discharged from the ink jet head with respect to the inner area ofthe bank layer “bank”, and the organic semiconductor films SA and SB areformed in the inner area of the bank layer “bank”. As a result, alight-shielding bank layer “bank” is formed between the pixel electrodePEA of the first pixel section PXA and the pixel electrode PEB of thesecond pixel section PXB.

Further, in the first and second thin-film optoelectronic transducers11A and 11B, the transparent pixel electrode PEA or PEB formed of ITO,the positive-hole injection layer VA, and the organic semiconductor filmSA as a light-emission thin film are multilayered, and further, acounter electrode OP formed of a lithium-containing metal film such asaluminum or calcium is formed on the surface of the organicsemiconductor film SA in this sequence. In contrast, when a drivingcurrent is made to flow in a reverse direction to the first and secondthin-film optoelectronic transducers, there is a case in which, from thelower layer side toward the upper layer side, a pixel electrode PEA orPEB formed of an ITO film, a counter electrode OP formed of alithium-containing aluminum electrode, which is so thin as to have alight transmission property, an organic semiconductor film SA, apositive-hole injection layer VA, and a counter electrode OP (positivepole) formed of a lithium-containing metal film such as aluminum orcalcium are multilayered in this sequence, forming a light-emittingelement 40.

(Driving Circuit)

As can be seen from FIG. 6, the counter electrode OP is formed at leaston the pixel area, and is formed in strip in such a manner so as toextend across a plurality of pixels PX as a common electrode among thepixels PX. The counter electrode OP is held at a fixed potential.

In this embodiment, the construction is formed as described below suchthat in all the pixels PX, the first and second thin-film optoelectronictransducers 11A and 11B can be used as a light-emitting element or alight-receiving element, and one of the first and second thin-filmoptoelectronic transducers 11A and 11B can be used as a light-emittingelement and the other as a light-receiving element.

Referring again to FIG. 5, a data-side driving circuit 30 for outputtinga signal for controlling the switched on/off state and a signal forcontrolling the light-receiving/non-light-receiving state to the firstwiring D21 is formed on the transparent substrate 2. Also formed on thetransparent substrate 2 are a first photocurrent detection circuit 501for detecting photocurrent from the second wiring D22 which flows whenthe first thin-film optoelectronic transducer 11A receives light, and asecond photocurrent detection circuit 502 for detecting photocurrentfrom the third wiring D23 which flows when the second thin-filmoptoelectronic transducer 11B receives light. Here, the firstphotocurrent detection circuit 501 and the second photocurrent detectioncircuit 502 contain a very-small-current amplification circuit, avoltage amplification circuit, and the like therein, so that a verysmall variation of each wiring is monitored.

(Switching Circuit)

As shown in FIG. 5, formed on the transparent substrate 2 are a firstswitching circuit 401 which connects the second wiring D22 to a commonpower-supply line com when the first thin-film optoelectronic transducer11A is used as a light-emitting element and which connects the secondwiring D22 to the first photocurrent detection circuit 501 when thefirst thin-film optoelectronic transducer 11A is used as alight-receiving element, and a second switching circuit 402 whichconnects the third wiring D23 to the common power-supply line corn whenthe second thin-film optoelectronic transducer 11B is used as alight-emitting element and which connects the third wiring D23 to thesecond photocurrent detection circuit 502 when the second thin-filmoptoelectronic transducer 11B is used as a light-receiving element.

In this example, the first switching circuit 401 is formed by signallines cg1 and sg1 to which two signals whose high level and low levelare inverted with respect to the other are respectively supplied, andthe second switching circuit 402 is formed by signal lines cg2 and sg2to which two signals whose high level and low level are inverted withrespect to the other are respectively supplied. These signal lines cg1,sg1, cg2, and sg2 are connected to the gate electrodes of n-channel-typeTFTs 45, 46, 47, and 48, respectively. Here, the TFT 45 is constructedso as to control the connected state of the common power-supply line comand the second wiring D22, and the TFT 46 is constructed so as tocontrol the connected state of the first photocurrent detection circuit501 and the second wiring D22. Similarly, the TFT 47 is constructed soas to control the connected state of the common power-supply line comand the third wiring D23, and the TFT 48 is constructed so as to controlthe connected state of the second photocurrent detection circuit 502 andthe third wiring D23.

(Method of Use)

When the image sensor apparatus 1 having an additional display devicefunction constructed as described above is used as a contact-type imagesensor apparatus, a readout object, such as a photograph, from which animage is to be read, is brought into close contact with the rear surfaceof the transparent substrate 2. Here, in each pixel PX, when the firstthin-film optoelectronic transducer 11A is used as a light-emittingelement and the second thin-film optoelectronic transducer 11B as alight-receiving element, the first switching circuit 401 causes the TFT45 to be turned on and the TFT 46 to be turned off. In contrast, thesecond switching circuit 402 causes the TFT 47 to be turned off and theTFT 48 to be turned on.

In this state, the signals of waveforms shown in FIGS. 8(A) and 8(B) areoutput to the scanning line “gate” and the first wiring D21.

FIGS. 8(A) and 8(B) show a scanning signal Vgate supplied to eachscanning line “gate” in two adjacent pixels PX (the pixel PX11 on thepre-stage side, and the pixel PX21 on the post-stage side) in thedirection in which the first to third wirings D21, D22, and D23 areextended (the direction orthogonal to the scanning line “gate”), asignal VD12 for controlling the switch on/off (controllinglight-reception/non-light-reception), which is supplied to the firstwiring D21, the potential level (the potential level of the commonpower-supply line com) of the second wiring D22, the potentialfluctuation of the third wiring D23, and the potential fluctuation ofthe potential holding electrodes 65 of the first and second thin-filmoptoelectronic transducers 11A and 11B, and the potential level of thecounter electrode OP.

As can be seen from FIGS. 8(A)-(B), a scanning signal Vgate for causingthe first TFTs 10C and 10E to be turned on/off and selecting each pixelin sequence is supplied to the scanning line “gate”. Furthermore, aswitch on/off control signal VD21 for switching between the firstthin-film optoelectronic transducer 11A and the second wiring D22between a conduction state and an insulation state by turning on/off thesecond TFT 10D is supplied to the first wiring D21. At the same time,the signal VD21 causes the second TFT 10F to be turned on/off so as toswitch between the second thin-film optoelectronic transducer 11B andthe third wiring D23 between a conduction state and an insulation state.

Therefore, in the pixel PX selected by the scanning signal Vgate, in thefirst pixel section PXA, the first thin-film optoelectronic transducer11A changes from the switched-off state to the switched-on state inaccordance with the signal VD21 for switched on/off control, and thisswitched-on state is maintained. During this period, in the second pixelsection PXB, light which is radiated from the first pixel section PXAonto a readout object, such as a photograph, is reflected, and thereflected light is received by the second thin-film optoelectronictransducer 11B. As a result, photocurrent flows in the second thin-filmoptoelectronic transducer 11B, and in accordance with this, apredetermined potential difference is generated between the pixelelectrode PEB of the second thin-film optoelectronic transducer 11B andthe counter electrode OP. This potential difference can be detected insequence by the second photocurrent detection circuit 502 through thethird wiring D23. Such an operation is performed in each pixel insequence in accordance with a scanning signal output to the scanningline “gate” from the scanning-side driving circuit 20. Therefore, it ispossible for the image sensor apparatus 1 having an additional displaydevice function as a contact-type image sensor apparatus to read imageinformation from a readout object, such as a photograph.

The image information read in this way and the like can be displayed bythe image sensor apparatus 1 having an additional display devicefunction. That is, the image information read herein from a photographor the like is recorded in an information recording device, such as aRAM, and when it is displayed, a modulation image signal in accordancewith the image information is sent to the first wiring D21 from thedata-side driving circuit 30. As a result, in the pixel PX selected insequence by a scanning signal supplied from the scanning line “gate”,the switched on/off state of the first thin-film optoelectronictransducer 11A of the first pixel section PXA is controlled inaccordance with the modulation image signal, and a desired image isdisplayed.

When such a display operation is performed, if the second switchingcircuit 402 causes the TFT 48 to be turned off and the TFT 47 to beturned on and the third wiring D23 is connected to the commonpower-supply line com, in the pixel PX which is selected in sequence inaccordance with the scanning signal supplied from the scanning line“gate”, the switched on/off state of the second thin-film optoelectronictransducer 11B of the second pixel section PXB can be controlled inaccordance with the modulation image signal sent from the data-sidedriving circuit 30 to the first wiring D21. When the display operationis performed by both the first and second pixel sections PXA and PXB, itis possible to produce a display having higher luminance.

If the first and second switching circuits 401 and 402 cause the TFTs 46and 48 to be turned on and the TFTs 45 and 47 to be turned off, it ispossible to use each of the first and second thin-film optoelectronictransducers 11A and 11B as a light-receiving element in both the firstand second pixel sections PXA and PXB. As a result of the above, areading operation with higher sensitivity is possible.

(Advantages of this Embodiment)

As has been described above, in the image sensor apparatus 1 having anadditional display device function of this embodiment, since each pixelPX is formed with the first and second thin-film optoelectronictransducers 11A and 11B that function as a light-emitting element and alight-receiving element, by only changing the method of driving thesethin-film optoelectronic transducers, it is possible to use the imagesensor apparatus 1 having an additional display device function as animage sensor apparatus and a display device. Further, in the imagesensor apparatus 1 having an additional display device function of thisembodiment, each element can be manufactured by a semiconductor processand since an optical system, a mechanical system, sensors, illumination,and the like, which are expensive, are not required, the readout sectionof a facsimile machine and the like can be lowered in price.

Furthermore, by only switching the connected state of the second andthird wirings D22 and D23 by the switching circuits 401 and 402, it ispossible to cause both the first and second pixel sections PXA and PXBto function as a light-emitting section or a light-receiving section,and it is also possible to cause one of them to function as alight-emitting section and the other to function as a light-receivingsection.

Furthermore, since a light-shielding bank layer “bank”is formed betweenthe pixel electrode PEA of the first pixel section PXA and the pixelelectrode PEB of the second pixel section PXB, even if light is emittedin all directions from the side of the first pixel section PXA whichfunctions as a light-emitting section, it is possible for the bank layer“bank” to prevent the light from leaking to the second pixel section PXBwhich functions as a light-receiving section. Therefore, it is possibleto read an image from a readout object at a high S/N ratio.

Third Embodiment

This embodiment is of a construction similar to that of the firstembodiment, and differences will be described. In the above-describedfirst and second embodiments, the boundary portion between the formationarea of the pixel electrode PEA of the first thin-film optoelectronictransducer 11A and the formation area of the pixel electrode PEB of thesecond thin-film optoelectronic transducer 11B is in a straight line,whereas, in this embodiment, as shown in FIGS. 9(A) and 9(B), theformation area of the pixel electrode PEA of the first thin-filmoptoelectronic transducer 11A and the formation area of the pixelelectrode PEB of the second thin-film optoelectronic transducer 11B areintermingled with each other. With such a construction, when the imagesensor apparatus 1 having an additional display device function is usedas an image sensor apparatus, the light which is output from the firstpixel section PXA is reflected by a readout object such as a photograph,and efficiently reaches the second pixel section PXB. Even with theconstruction as described above, formation of a light-shielding layer“bank” between the pixel electrode PEA of the first pixel section PXAand the pixel electrode PEB of the second pixel section PXB makes itpossible for the bank layer “bank” to prevent the light from leaking tothe second pixel section PXB which functions as a light-receivingsection even if light is emitted in all directions from the side of thefirst pixel section PXA.

Fourth Embodiment

This embodiment is also similar to the first embodiment, and differenceswill be described. In this embodiment, for example, as shown in FIG. 10,if the formation area of the pixel electrode PEA of the first thin-filmoptoelectronic transducer 11A is surrounded by the formation area of thepixel electrode PEB of the second thin-film optoelectronic transducer11B, in comparison with a construction in which the outer frames of thegate electrodes are partitioned by a straight line, it is possible forthe center-of-gravity position of the formation area of the pixelelectrode PEA of the first thin-film optoelectronic transducer 11A to beclose to the center-of-gravity position of the formation area of thepixel electrode PEB of the second thin-film optoelectronic transducer11B, in spite of the fact that the formation area of the pixel electrodePEB is wide.

With this construction, when the image sensor apparatus 1 having anadditional display device function is used as an image sensor apparatus,since the center-of-gravity positions (the center positions of lightemission and reception) of the pixel electrodes PEA and PEB are close toeach other, the light which is output from the first pixel section PXAis reflected by a photograph or the like and efficiently reaches thesecond pixel section PXB.

Also with this construction, if a light-shielding bank layer “bank” isformed between the pixel electrode PEA of the first pixel section PXAand the pixel electrode PEB of the second pixel section PXB, even iflight is emitted in all directions from the side of the pixel sectionPXA, it is possible for the bank layer “bank” to prevent the light fromleaking to the second pixel section PXB that functions as alight-receiving section.

Fifth Embodiment

This embodiment is also similar to the first embodiment, and differenceswill be described. In this embodiment, as shown in FIG. 11(A), it ispreferable that the formation area of the pixel electrode PEA of thefirst thin-film optoelectronic transducer 11A be in the central portionof the formation area of the pixel electrode PEB of the second thin-filmoptoelectronic transducer 11B. With this construction, thecenter-of-gravity positions of both the formation area of the pixelelectrode PEA of the first thin-film optoelectronic transducer 11A andthe formation area of the pixel electrode PEB of the second thin-filmoptoelectronic transducer 11B completely overlap each other. Therefore,as shown in FIG. 11(B), when the light hv which is output from the firstpixel section PXA is reflected by a readout object, such as a photographor a document, and reaches the second pixel section PXB, since the peaksof the intensity distribution of the radiation light to the readoutobject and the intensity distribution of the reflected light from thereadout object are in the central portion of the pixel PX, in the secondpixel section PXB, the light is received with high efficiency over theentire surface of the pixel electrode PEB of the second thin-filmoptoelectronic transducer 11B.

Industrial Applicability

As has been described above, in the image sensor apparatus having anadditional display device function of the present invention, since firstand second thin-film optoelectronic transducers which function as alight-emitting element and a light-receiving element are formed in eachpixel, by only changing the method of driving these thin-filmoptoelectronic transducers, the image sensor apparatus having anadditional display device function can be used as either an image sensorapparatus or a display device. Furthermore, in the image sensorapparatus having an additional display device function of thisembodiment, each element can be manufactured by a semiconductor process,and an optical system, a mechanical system, sensors, illumination, andthe like, which are expensive, are not required. Therefore, the readoutsection of a facsimile machine or the like can be lowered in price.

What is claimed is:
 1. An image sensor apparatus having an additionaldisplay device function, the apparatus including a plurality of pixelsarranged in matrix, scanning lines supplied with a scanning signal forselecting the pixels in sequence, and a first wiring, a second wiringand a third wiring used as signal lines when light emission or lightreception is performed by the pixels selected by said scanning signal,each of said pixels comprising: a first pixel section including a firstconduction control circuit supplied with said scanning signal throughsaid scanning line, and a first thin-film optoelectronic transducer thatperforms light emission or light reception, connected to said firstwiring and said second wiring via the first conduction control circuit;and a second pixel section including a second conduction control circuitsupplied with said scanning signal through said scanning line, and asecond thin-film optoelectronic transducer that performs light emissionor light reception, connected to said first wiring and said third wiringvia the second conduction control circuit.
 2. The image sensor apparatushaving an additional display device function according to claim 1, saidfirst conduction control circuit and said second conduction controlcircuit each being composed of a thin-film transistor having a gateelectrode, a source region and a drain region, and being supplied withsaid scanning signal to the gate electrode, said thin-film transistor ofsaid first conduction control circuit being connected at one of thesource region and the drain region to said second wiring and connectedat another of the source region and the drain region to a pixelelectrode of said first thin-film optoelectronic transducer, and saidthin-film transistor of said second conduction control circuit beingconnected at one of the source region and the drain region to said thirdwiring and connected at another of the source region and the drainregion to a pixel electrode of said second thin-film optoelectronictransducer.
 3. The image sensor apparatus having an additional displaydevice function according to claim 2, further comprising a switchingcircuit that controls connection to the first wiring, the second wiringand the third wiring such that, when one of said first thin-filmoptoelectronic transducer and said second thin-film optoelectronictransducer is used as a light-emitting element, one wiring of saidsecond wiring and said third wiring to which the one thin-filmoptoelectronic transducer is connected to an output circuit for a switchon/off control signal, when said one thin-film optoelectronic transduceris used as a light-receiving element, the one wiring of said secondwiring and said third wiring to which the one thin-film optoelectronictransducer is connected to a photoelectric current detection circuit,and said first wiring is connected to a constant-voltage power source.4. The image sensor apparatus having an additional display devicefunction according to claim 1, said first conduction control circuit andsaid second conduction control circuit respectively comprising: a firstthin-film transistor having a gate electrode supplied with said scanningsignal, and a second thin-film transistor having a gate electrodeconnected to said first wiring through the first thin-film transistor,said second thin-film transistor of said first conduction controlcircuit further having one of a source region and a drain regionconnected to said second wiring and another of the source region and thedrain region connected to a pixel electrode of said first thin-filmoptoelectronic transducer, and said second thin-film transistor of saidsecond conduction control circuit further having one of a source regionand a drain region connected to said third wiring and another of thesource region and the drain region connected to a pixel electrode ofsaid second thin-film optoelectronic transducer.
 5. The image sensorapparatus having an additional display device function according toclaim 4, further comprising a switching circuit that controls connectionto the first wiring, the second wiring and the third wiring such that,when one of said first thin-film optoelectronic transducer and saidsecond thin-film optoelectronic transducer is used as a light-emittingelement, one wiring of said second wiring and third wiring to which theone thin-film optoelectronic transducer is connected is connected to aconstant-voltage power source, when said one thin-film optoelectronictransducer is used as a light-receiving element, the one wiring of saidsecond wiring and said third wiring to which the one thin-filmoptoelectronic transducer is connected is connected to a photoelectriccurrent detection circuit, and said first wiring is connected to anoutput circuit for receiving a signal for controlling a conduction stateof said second thin-film transistor.
 6. The image sensor apparatushaving an additional display device function according to claim 1, aformation area of a pixel electrode of said first thin-filmoptoelectronic transducer and a formation area of a pixel electrode ofsaid second thin-film optoelectronic transducer being intermingled witheach other.
 7. The image sensor apparatus having an additional displaydevice function according to claim 1, a formation area of a pixelelectrode of said first thin-film optoelectronic transducer and aformation area of a pixel electrode of said second thin-filmoptoelectronic transducer having a center-of-gravity position and beingprovided such that the center-of-gravity position of both are close toeach other in comparison with a construction in which an outer frame ofeach pixel electrode is partitioned by a straight line.
 8. The imagesensor apparatus having additional display device function according toclaim 1, a formation area of a pixel electrode of said first thin-filmoptoelectronic transducer being surrounded by a formation area of apixel electrode of said second thin-film optoelectronic transducer. 9.An image sensor apparatus having an additional display device function,the apparatus including a plurality of pixels arranged in matrix,scanning lines supplied with a scanning signal for selecting the pixelsin sequence, and a first wiring, a second wiring and a third wiring usedas signal lines when light emission or light reception is performed bythe pixels selected by said scanning signal, each of said pixelscomprising: a first pixel section including a first conduction controlcircuit supplied with said scanning signal through said scanning line,and a first thin-film optoelectronic transducer that performs lightemission or light reception, connected to said first wiring and saidsecond wiring via the first conduction control circuit; and a secondpixel section including a second conduction control circuit suppliedwith said scanning signal through said scanning line, and a secondthin-film optoelectronic transducer that performs light emission orlight reception, connected to said first wiring and said third wiringvia the second conduction control circuit, a center-of-gravity of aformation area of a pixel electrode of said first thin-filmoptoelectronic transducer and a center-of-gravity of a formation area ofa pixel electrode of said second thin-film optoelectronic transducerbeing sufficiently close to each other in comparison with a size of eachpixel electrode.
 10. The image sensor apparatus having an additionaldisplay device function according to claim 1, further comprising alight-shielding layer formed between a pixel electrode of said firstthin-film optoelectronic transducer and a pixel electrode of said secondthin-film optoelectronic transducer.
 11. The image sensor apparatushaving an additional display device function according to claim 9,further comprising a light-shielding layer formed between the pixelelectrode of said first thin-film optoelectronic transducer and thepixel electrode of said second thin-film optoelectronic transducer. 12.An active matrix display device including a plurality of pixels arrangedin matrix, scanning lines supplied with a scanning signal for selectingthe pixels in sequence, and a first wiring, a second wiring and a thirdwiring used as signal lines when light emission or light reception isperformed by the pixels selected by said scanning signal, each of saidpixels comprising: a first pixel section including a first conductioncontrol circuit supplied with said scanning signal through said scanningline, and a first thin-film optoelectronic transducer that performslight emission or light reception, connected to said first wiring andsaid second wiring via the first conduction control circuit; and asecond pixel section including a second conduction control circuitsupplied with said scanning signal through said scanning line, and asecond thin-film optoelectronic transducer that performs light emissionor light reception, connected to said first wiring and said third wiringvia the second conduction control circuit.
 13. The active matrix displaydevice according to claim 12, said first conduction control circuit andsaid second conduction control circuit are each composed of a thin-filmtransistor having a gate electrode, a source region and a drain region,and being supplied with said scanning signal to the gate electrode, saidthin-film transistor of said first conduction control circuit isconnected at one of the source region and the drain region to saidsecond wiring and connected at another of the source region and thedrain region to a pixel electrode of said first thin-film optoelectronictransducer, and said thin-film transistor of said second conductioncontrol circuit is connected at one of the source region an d the drainregion to said third wiring and connected at another of the sourceregion and the drain region to a pixel electrode of said secondthin-film optoelectronic transducer.
 14. The active matrix displaydevice according to claim 13, further comprising a switching circuitthat controls connection to the first wiring, the second wiring and thethird wiring such that, when one of said first thin-film optoelectronictransducer and said second thin-film optoelectronic transducer is usedas a light-emitting element, one wiring of said second wiring and saidthird wiring to which the one thin-film optoelectronic transducer isconnected to an output circuit for a switch on/off control signal, whensaid one thin-film optoelectronic transducer is used as alight-receiving element, the one wiring of said second wiring and saidthird wiring to which the one thin-film optoelectronic transducer isconnected to a photoelectric current detection circuit, and said firstwiring is connected to a constant-voltage power source.
 15. The activematrix display device according to claim 12, said first conductioncontrol circuit and said second conduction control circuit respectivelycomprising: a first thin-film transistor having a gate electrodesupplied with said scanning signal, and a second thin-film transistorhaving a gate electrode connected to said first wiring through the firstthin-film transistor, said second thin-film transistor of said firstconduction control circuit further having one of a source region and adrain region connected to said second wiring and another of the sourceregion and the drain region connected to a pixel electrode of said firstthin-film optoelectronic transducer, and said second thin-filmtransistor of said second conduction control circuit further having oneof a source region and a drain region connected to said third wiring andanother of the source region and the drain region connected to a pixelelectrode of said second thin-film optoelectronic transducer.
 16. Theactive matrix display device according to claim 15, further comprising aswitching circuit that controls connection to the first wiring, thesecond wiring and the third wiring such that, when one of said firstthin-film optoelectronic transducer and said second thin-filmoptoelectronic transducer is used as a light-emitting element, onewiring of said second wiring and third wiring to which the one thin-filmoptoelectronic transducer is connected is connected to aconstant-voltage power source, when said one thin-film optoelectronictransducer is used as a light-receiving element, the one wiring of saidsecond wiring and said third wiring to which the one thin-filmoptoelectronic transducer is connected is connected to a photoelectriccurrent detection circuit, and said first wiring is connected to anoutput circuit for receiving a signal for controlling a conduction stateof said second thin-film transistor.
 17. The active matrix displaydevice according to claim 12, a formation area of a pixel electrode ofsaid first thin-film optoelectronic transducer and a formation area-of apixel electrode of said second thin-film optoelectronic transducer beingintermingled with each other.
 18. The active matrix display deviceaccording to claim 12, a formation area of a pixel electrode of saidfirst thin-film optoelectronic transducer and a formation area of apixel electrode of said second thin-film optoelectronic transducerhaving a center-of-gravity position and being provided such that thecenter-of-gravity position of both are close to each other in comparisonwith a construction in which an outer frame of each pixel electrode ispartitioned by a straight line.
 19. The active matrix display deviceaccording to claim 12, a formation area of a pixel electrode of saidfirst thin-film optoelectronic transducer being surrounded by aformation area of a pixel electrode of said second thin-filmoptoelectronic transducer.
 20. An active matrix display device,including a plurality of pixels arranged in matrix, scanning linessupplied with a scanning signal for selecting the pixels in sequence,and a first wiring, a second wiring and a third wiring used as signallines when light emission or light reception is performed by the pixelsselected by said scanning signal, each of said pixels comprising: afirst pixel section including a first conduction control circuitsupplied with said scanning signal through said scanning line, and afirst thin-film optoelectronic transducer that performs light emissionor light reception, connected to said first wiring and said secondwiring via the first conduction control circuit; and a second pixelsection including a second conduction control circuit supplied with saidscanning signal through said scanning line, and a second thin-filmoptoelectronic transducer that performs light emission or lightreception, connected to said first wiring and said third wiring via thesecond conduction control circuit, a center-of-gravity of a formationarea of a pixel electrode of said first thin-film optoelectronictransducer and a center-of-gravity of a formation area of a pixelelectrode of said second thin-film optoelectronic transducer beingsufficiently close to each other in comparison with a size of each pixelelectrode.
 21. The active matrix display device according to claim 12,further comprising a light-shielding layer formed between a pixelelectrode of said first thin-film optoelectronic transducer and a pixelelectrode of said second thin-film optoelectronic transducer.
 22. Theactive matrix display device according to claim 20, further comprising alight-shielding layer formed between the pixel electrode of said firstthin-film optoelectronic transducer and the pixel electrode of saidsecond thin-film optoelectronic transducer.